Revert "Log dlopen errors in opt builds (flutter#41477)" (flutter#43677)

This reverts commit 321f801.

This didn't seem to help with debugging b/276657840. Fixes flutter/flutter#125523.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

fml/platform/posix/native_library_posix.cc

@@ -13,10 +13,8 @@ NativeLibrary::NativeLibrary(const char* path) {
   ::dlerror();
   handle_ = ::dlopen(path, RTLD_NOW);
   if (handle_ == nullptr) {
-    // TODO(jiahaog): Use FML_DLOG:
-    // https://github.com/flutter/flutter/issues/125523
-    FML_LOG(ERROR) << "Could not open library '" << path << "' due to error '"
-                   << ::dlerror() << "'.";
+    FML_DLOG(ERROR) << "Could not open library '" << path << "' due to error '"
+                    << ::dlerror() << "'.";
   }
 }